Technical Abstract:
The performance of a farm-scale, multistage treatment system for swine manure was evaluated seasonally during the initial year and half of operation to determine the extent of disinfection corresponding to each stage of the process. This treatment system eliminates the direct lagoon storage of swine house discharge liquids and substitutes immediate treatment by enhanced separation of solids from liquids, using polyacrylamide (PAM) polymer to reduce 98% of suspended solids and considerable BOD and COD. After enhanced solids separation, acclimation and immobilization techniques, involving an aerated nitrification step followed by denitrification, are used to remove biological N. The process concludes with P extraction by pH monitored and controlled lime precipitation. The resulting cleaned effluent is then used in part as clean flush water for the swine houses, or is stored until sprayed onto fields. The final effluent and each of the steps in the process were evaluated for their content of total and fecal coliforms, fecal Enterococcus, Salmonella spp., Clostridium perfringens, and coliphage. The microbial quality of the process effluent was compared to the lagoon effluent used for spray field irrigation. Treated lagoon and untreated lagoon storage liquids were compared. Solids pre- and post composting with cotton gin trash and bark in a channel mechanically agitated, aerated system showed substantial reduction in pathogen indicators during the thermophilic phases, with further stabilization dependent on subsequent curing in static windrows retained for at least 30 da.